diff --git a/tox.ini b/tox.ini
index aecb5ef2..06c17c6d 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,9 @@ setenv =
 	DJANGO_SETTINGS_MODULE = tests.settings
 	PYTHONWARNINGS = always
 	PYTHONDONTWRITEBYTECODE = 1
+	# Use a non-existent file to prevent boto3 from loading
+	# any configuration from the user's environment
+	AWS_CONFIG_FILE = {toxinidir}/tests/no_such_file.conf
 commands = pytest --cov=storages tests/ {posargs}
 deps =
 	cryptography